sli certified upto two 8800gtx's? but has three sets of power chords

[sulot00]

i'm about to convert to sli ( 8800gtx superclocked x2) I was looking at some 850 ish watt psu's on newegg and there are some deals. but i see several of that range with three sets (pairs) of chords for my gpus but the psu says sli certified upto 2 gtx's or ultras. could i run 3 cardds eventually? or does it mean you could run three cards, just not three gtx or ultras? i wish the descriptions/specs were more specific. i'll probably get a 780i ftw soon and i only have two gpu right now but in a few months i could always throw another in. my point is, if i wanted to , could i? or do i need a more expensive supply. I know 850 watt is plenty for two cards. I think its possible it could handle three but i know you should always have more than you need for stability sake. and why advertise their certification or support which is less than the chords supplied with it? wierd .. anyways maybe someone can clear that up for me. and then there is certified vs. supported . i assume certified is better, but what is the technicality that separates the two. nvidia vouches or something?

quite the brain drool i left there for you,
thanks in advance , i could really use some quality insight
heres what i have and could potentially upgrade too (too cheap not to)

currently have:
q6600
ab9pro
8g corsair ddr2 800 (6400)
two harddrives
two optical drives
8800gtx superclocked
around 5 or 6 fans half 90/ half 120

definate upgrades in the works:
780i/ftw
additional 8800gtx superclocked
psu
oc my cpu

possible upgrades within a few months:
3rd gpu whether it be a professional card or third gtx for tri sli

 

[dirtmountain]

Can the 8800GTX tri SLI ? or is it just the Ultra? Anyways here's a chart showing GPU power usage.
http://forums.atomicmpc.com.au/index.php?showtopic=264
power supply calculator
http://extreme.outervision.com/psucalculatorlite.jsp

 

[faster3200]

Like dirt, i am not sure about tri sli working, but I think it will, it looks like it has two connectors for SLI bridges.

It is more important to buy a quality psu than a psu with high wattage. Looking at 12v rail amperage and stability along with the rated temp is also more important than overall wattage. I recommend reading through JonnyGuru's website and forums. They should provide you with all the info you need.

That said I would highly recommend the Antec Signature 850w if you can afford it. It is one of the best on the market and has the best rail stability in its price range.

I think Maximum PC uses the PC P&C 750w psu almost every year, and they have some pretty insane hardware.

 

[V3NOM]

oi man you don't need 850W... read my thread and follow the link to thermaltake.outervision... you don't even need 850W for TWO 9800GX2's!

 

[sulot00]

thanks for the advice guys. I have read a bit about amperage so i know a bit more than the laman but i also dont want to take any chances. I will check out the links posted and try to educate myself further on their actual power draw. as for the tri-sli support/ gtx. I believe it does I think i read that on evga or another reputable spot that ultras and gtx's are both supported or are only supported for tri-sli. they are in fact quite identical boards at least in specs and power drain depending on how much they are overclocked. i would think i would need an 850 just for two just to be safe, but i will definately check out the links.
if i have specific model / brand dilemas or "is two 30 amperage rails enough" kind of question i'll be sure to add further posts.

 

[sulot00]

what about something like this from an up and comer with a good rep thus far?
http://www.newegg.com/Product/Product.aspx?Item=N82E16817128017

 

[invisik]

hiper isnt it a 3 or 4 tier?
go with antec, pc power & cooling, corsair or thermaltake 700w should be enough.

 

[sulot00]

I checked out the nvidia recommended power supplies here http://www.slizone.com/object/slizone_build_psu.html and if i ever want 3 cards that eat up as much as a 8800gtx superclocked or ultra , they are recommending 1000 watts on most of the suggested psus. which sounds good n all because models like the Real Power Pro 1250W have 6 independent 12v rails for my 6 pci express connections but are they just playin it safe or what? keep in mind, i will be adding a 3rd card at some point. i mean i have a 550 or 650 watt corsair now but even it has two pci express connections used . its just kind of scary cuz even if i find one with 3 pairs of 6 pin connectors (or some 6+2) , i need to know that the rails are distributed properly through the chords too. i'm still lookin but i thought that nvida page was interesting enough to bring up. i found it while going through the recommended links . fyi the calculator link said i'm around 580 ish and i even put in dual cards i think. but under load i know the cards pull a lot. oh, and the calculator offers sli option but not how many cards specifically. i guess they want you to spend the 2 bux to get the accurate reading.

 

[faster3200]

Split rails (multiple 12v) is bad. You want as much amperage on as few a rails as possible as that ensures that you are getting all of your power (I won't go into detail). The psus nvidia recommends are really overkill, all companies do this.

Go with any of the above recommend psus and you will be fine.

The psu calculator isn't super accurate fyi.

 

[sulot00]

okay so i looked at the psus recommended above, i'm willing to purchase the psus recommended by you guys but what will I do about adding a third card? the antec and pc power have only 4pci connects and the pc power goes as far as saying sli certified for 2 8800gtx's and below. now, if you guys are saying I dont need more power, thats great i'll buy right now, but how will i connect my third card? the molex adapters? and then how do I distribute that? will the psu manual show me which chords utilize each real so I'll know which card gets the right distribution. I know that theywill likely keep the pci express evenly separated among the two high amp rails but what about the third? sorry if this is getting redundant i just want to be sure.
thanks again! this is all very helpful and reassuring

 

[faster3200]

the antec and pc power have only 4pci connects and the pc power goes as far as saying sli certified for 2 8800gtx's and below. now, if you guys are saying I dont need more power, thats great i'll buy right now, but how will i connect my third card? the molex adapters? and then how do I distribute that? will the psu manual show me which chords utilize each real so I'll know which card gets the right distribution.

Molex connectors will work for the third card.

The PC P&C psu has a single 12v rail so there is no need to worry about distribution. The antec has the following distribution:

12V1 - black modular connectors, Molexes, SATA
12V2 - EPS12V, ATX12V connectors
12V3 - one red modular connector, PCI-E 8 pin #1
12V4 - other red modular connector, PCI-E 8 pin #2

 

[sulot00]

so this is a safe setup?:
12v1 2x pci-e 6 pins to one card
molex 1 to card 2
molex 2 to card 3
modulars and molex to drives
12v2 to mb power etc
12v3 to card 2
12v4 to card 3
I thought that I've read a gtx / ultra can draw upto 11 amps under load
its seems like a lot to bear on the first rail , especially since its only 22amps

 

[sulot00]

you know what , i think i'll go for the pc power , the single rail is reassuring and its cheap. thanks guys!